1. Technical Field
Example embodiments of the present invention relate in general to technology for ensuring network continuity, and more particularly, to an apparatus and method for providing a seamless Internet service to a terminal while supporting several types of uplink mobile communication signals, such as a third generation (3G) signal, a 4G signal, and a satellite signal.
2. Related Art
Along with the development of information and communications technology, demands for accessing the Internet regardless of a location have risen. In particular, due to a recent increase in the use of smart phones and tablet personal computers (PCs), such demands are further increasing. As technology related to the demands, mobile Internet protocol (IP) technology is intended to support mobility of a terminal connected to the Internet. In order for a terminal to be connected with the Internet at all times while moving, it is necessary to solve many problems. Fundamentally, the Internet is configured in the form of several subnets connected through routers, and the routers transmit packets based on network prefixes. Therefore, it is difficult for a mobile node (MN) moving from one subnet to another subnet to maintain its Internet connection. In other words, in order for the MN to perform communication in the other subnet, the MN is required to be assigned a new IP address in the other subnet, but the change of the IP address denotes disconnection in the transport layer that is an upper layer in terms of an IP. In existing Internet technology, an IP address is information that distinguishes a terminal from others and also denotes the location of the terminal fundamentally, and thus it is not possible to forward a packet to the variable location of a moving terminal.
As a mobile IP for forwarding packets sent to an existing IP address to a current location of the terminal in this environment, there are mobile Internet protocol version 4 (MIPv4), mobile Internet protocol version 6 (MIPv6), and so on. According to these existing methods, a tunnel is created from an original location (home address) denoted by an IP address to a current location (temporary address), and packets are forwarded to the moving terminal. In other words, all packets to be forwarded to the mobile terminal are first sent to a home agent (HA) in which the mobile terminal has been registered, and the HA forwards the packets to the mobile terminal through the tunnel. Here, the tunnel is established between the HA and the mobile terminal. Also, every time the mobile terminal moves, an existing location of the tunnel is updated with a current location. In this case, all terminals are only required to generate packets with transmission and reception IP addresses using the existing IP as is and transfer the packets to routers.
However, every time the location of a mobile terminal changes, the mobile terminal is required to control location registration and tunnel creation for forwarding a packet from a fixed IP location to the mobile terminal at a current location. Since the load of maintaining a home address and tunnel creation is too much for the mobile terminal, a proxy mobile Internet protocol (PMIP) technology in which a network instead of a terminal serves a protocol for supporting mobility has been recently devised. The PMIP is a mobility management protocol in which a network component, instead of a terminal, present in a network and referred to as a proxy, processes tasks to be processed at a receiving end, such as registration of a current location and establishment of a tunnel from a fixed IP location to a current location. It is unnecessary for a terminal to update its location or establish a tunnel with a home address so as to forward a packet, and a proxy component present in a network processes these tasks.
However, it is not possible to use the above-described methods when the type of an uplink signal receivable at one location changes or it is not possible to receive any uplink signal because a network device for receiving a mobile communication signal and providing a wireless Internet signal to a terminal moves.